Thermal conducting tube shield



Nov. 4, 1958 L. R. WOODS ETAL THERMAL CONDUCTING TUBE SHIELD Filed Feb. 17. 1954 INVENTORS. LEROY R. WOODS By JAMES E. ROBERTS zww K ATTORNEY lifted States Patent assasss THERMAL corsnucrrsu; TUBE SHIELD Lerey R. Woods, Whittier, James E. Roberts, Long Beach, Calif, assignors, by mesne assignments, to International Eiectr-enic Research Corporation, a corporation of Qalii'ernia Applicatlcn February 17, 1954, Serial No. 413,927

4- Claims. (Cl. 315-85) (Filed under Rule 47(a) and 35 U. S. C. 116) This invention pertains to a novel electrostatic tube shield, and more particularly to an electrostatic tube shield adapted to remove the heat from the bulb of the tube which it encompasses and to cause the temperature gradient upon the surface of the bulb to be substantially zero.

It is frequently necessary to use an electrostatic shield around an electron tube to prevent interference with the operation thereof by stray electrical fields. When a conventional tube shield is placed over an electron tube, not only the temperature of the bulb increases by a large amount, but also the temperature gradient upon the sur face of the bulb becomes prohibitive. The presence of an appreciable temperature gradient upon the surface of the glass bulb creates stresses in the glass which makes the glass more susceptible to any increased stress due to mechanical vibration or acceleration.

The device contemplated by this invention not only reduces the temperature of the bulb of the enclosed electron tube, but also reduces the temperature gradient thereon to substantially zero.

It is therefore an object of this invention to provide means for reducing the temperature of the bulb of an electron tube.

It is another object of this invention to provide means for increasing the linearity of the temperature gradient upon the surface of the bulb of an electron tube.

It is still another object of this invention to provide means for reducing the temperature gradient to substantially zero upon the surface of the bulb of an electron tube.

It is yet another object of this invention to provide a novel heat-conducting electron tube shield.

Other objects of invention will become apparent from the following description taken in connection with the accompanying drawings, in which- Fig. l is a view, partly in section, of the novel tube shield of this invention, together with a typical electron tube enclosed therein;

Fig. 2 is a View taken at 2-2 in Fig. 1;

Fig. 3 is an oblique view, partly in section, of a typical shield of this invention, more particularly showing the improved portion thereof;

And Fig. 4 is a typical tube shield base to which the device of Fig. 3 is attached to provide heat conduction away from the shield.

In Figs. 1, 2, 3, and 4, tube shield 1 is shown surrounding a typical electron tube bulb 2. Tube 2 fits into socket 3. Tube shield base 4 is rigidly electrostatically and heat-conductively attached to chassis 5. Chassis 5 carries heat away by both conduction and radiation. Tube shield 1 is attached to tube shield base 4 by means of a bayonet connection, shown more particularly in connection with Figs. 3 and 4. Spiral spring 6 is positioned within tube shield 1 to engage the end of electron tube 2; to cause tube 2 to be mechanically centered within shield 1. The casing of shield 1 is preferably of a material 2- which has a very high heat conductivity such as, for example, silver, copper, or nickel. Alloys of these metals are sometimes used. Typical alloys of copper which are used are brass or beryllium-copper. Aplurality of rows 7, 8, and 9 of inwardly extending fiat springs are positioned circumferentially and uniformly about the axis 10 of tube 2. Each fiat spring contacts the bulb of tube 2. Each row 7, 8, and 9 of fiat springs contains a plurality of said flat springs substantially uniformly distributed in an axial direction along the outer radius of tube 2. Shield 1, shown herein, is of the type which has a plurality of windows circumferentially spaced around its exterior, as shown more particularly in Fig. 3. Rows of springs 7, 8, and 9 preferably extend to partially close these windows to thereby increase the electrostatic shielding of tube 2. Rows of springs 7, 8, and 9 are fabricated of a heat-conductive material such as, for example, silver, copper, or nickel, or the alloys of those elements. Beryllium-copper is particularly suitable because of its desirable mechanical spring characteristics. Rows of springs 7, 8, and 9 are heat-conductively attached to the outer frame of tube shield 1. This attachment may be accomplished by soldering or welding, for example, or by constructing springs 7, 8, and 9 as an integral part of the frame of tube shield 1. As shown in Figs. 2 and 3, rows of springs 7, 8, and 9 spiral inward toward axis 10 to mechanically engage the bulb of tube 2 to remove heat therefrom.

Thus, the improved tube shield of this invention not only reduces the temperature of the bulb of the electron tube which it encloses, but also decreases the temperature gradient to substantially zero upon the surface of the bulb.

Although the invention has been described and illustrated in detail, it is to be clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of this invention being limited only by the terms of the appended claims.

We claim:

1. In combination with an electron tube, a shield comprising a cylindrically shaped heat conducting cylinder enclosing said electron tube, means forming a plurality of heat conducting paths between said tube and said cylinder, said means comprising a plurality of finger rows, each said row extending substantially axially of said tube and said cylinder, each said row including a plurality of resilient heat conducting fingers, said rows being mutually circumferentially spaced along said tube and said cylinder, a plurality of longitudinally extending and circumferentially spaced windows in said cylinder, the number of said windows being equal to the number of said finger rows, means for securing one end of each said finger in each finger row to one edge of a corresponding window, each finger extending from said one end thereof to said tube and circumferentially of said tube and cylinder into resiliently maintained heat conductive contact with said tube, the fingers of each row being engaged with said tube along an axially extending substantially continuous portion thereof.

2. An electron tube shield comprising a heat conducting cylinder adapted to enclose an electron tube, means forming a plurality of heat conducting paths between an area within said cylinder and said cylinder, said means comprising a plurality of finger rows, each said row extending substantially axially of said cylinder and including a plurality of heat conducting fingers, said rows being mutually spaced circumferentially about said cylinder, each said finger having only one end thereof secured to said cylinder and extending from said one end inwardly and substantially in the direction of the circumference of said cylinder, said fingers being so shaped and constructed as to be adapted to make resilient heat conductive contact with such tube.

3. An electron tube shield comprising a heat conducting cylinder adapted to enclose an electron tube, means forming a plurality of heat conducting paths between said cylinder and an area within said cylinder, said means comprising a plurality of finger rows, each said row extending substantially axially of said cylinder and includ- 1 ing a plurality of heat conducting fingers, said rows being thereof inwardly and substantially in the direction of the 15 2,499,612

4 circumference of said cylinder, said fingers being so shaped and constructed as to be adapted to make resilient heat conductive contact with such tube.

4. A device as recited in claim 3 and further comprising means for heat-conductively attaching said shield to a heat radiating structure.

References (Iited in the file of this patent UNITED STATES PATENTS 1,962,968 Nowosielski June 12, 1934 2,100,042 Travis NOV. 23, 1937 2,419,234 Holihan Apr. 22, 1947 2,432,513 'Depew Dec. 16, 1947 Staver Mar. 7, 1950 

